JP2001321340A - Eye characteristics measurement device - Google Patents

Abstract

(57) [Summary] (With correction) [PROBLEMS] To measure the optical characteristics of an eye to be examined by taking a difference from a relationship with measurement data in a reference optical path, thereby obtaining a highly accurate measurement device. In particular, the present invention provides an eye characteristic measuring device including a reference optical system different from the measurement light receiving system. A reference optical system illuminates a minute area on a reflection surface of a reference reflector with a light flux from a first light source, and receives a light flux reflected from the reference reflector and returned.
The first conversion member 400 converts the reflected light beam received by the measurement optical system or the reference optical system into a plurality of beams, and the first light receiving unit 510 receives the plurality of light beams converted by the conversion member, and performs switching. The unit alternately guides the light beams of the measurement optical system and the reference optical system to the first light receiving unit, and the arithmetic and control unit controls the light receiving position of the light beam from the measurement optical system obtained by the first light receiving unit and the light reception position of the reference optical system. The optical characteristics of the eye 1000 can be obtained based on the light receiving position of the light beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring apparatus which performs high-precision measurement by measuring a difference from a relationship with measurement data in a reference optical path when measuring optical characteristics of an eye to be examined. In particular, the measurement light receiving system relates to an eye characteristic measuring device provided with another reference optical system.

[0002]

2. Description of the Related Art A measurement result of an eye characteristic measuring device includes both an eye aberration and an aberration of the measuring device. Therefore,
In order to cancel the aberration of the device, the measurement of the aberration of the device has been performed using a test object having no aberration in advance.

[0003]

However, in the above-mentioned conventional method, since the data measured at the beginning is used, it is included in the distortion of the equipment generated thereafter and the aberration of the equipment due to the deformation due to temperature and the like. There was a problem.

[0004] Therefore, there has been a strong demand for an eye characteristic measuring apparatus capable of completely removing aberrations at the time of measurement and performing extremely accurate measurement.

[0005]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned problems, and has a first light-emitting device for emitting a light beam of a first wavelength.
A light source, a measurement optical system for illuminating a light beam from the first light source toward the target surface of the eye to be inspected, and receiving a light beam reflected and returned from the target surface of the eye to be inspected; and A reference optical system for illuminating a minute area on the reflection surface of the reference reflector with the light flux of the reference reflector and receiving a light flux that is reflected back from the reference reflector, and the measurement optical system or the reference optical system. A first conversion member for converting the received reflected light beam into a plurality of beams, a first light receiving unit for receiving the plurality of light beams converted by the conversion member, the measurement optical system and the reference optical system A switching unit for alternately guiding the light beam to the first light receiving unit; and a light receiving position of the light beam from the measuring optical system and the light receiving position of the light beam from the reference optical system obtained by the first light receiving unit. And an arithmetic control unit for determining the optical characteristics of the optometry.

Further, the arithmetic and control unit of the present invention obtains setting data from an output signal of the first light receiving unit when receiving a light beam from the measuring optical system, and based on the setting data obtained here, It is also possible to configure so as to set the condition of the reference reflector of the reference optical system.

Further, the object surface of the eye to be examined according to the present invention is a retina of the eye to be examined, and the measuring optical system is configured to illuminate the retina of the eye to be examined in a minute area with a light beam from the first light source. The unit may be configured to determine the optical characteristics of the refractive power of the eye to be measured.

The eye surface to be inspected of the present invention is the cornea to be inspected, and the measuring optical system is configured to illuminate the light flux from the first light source substantially toward the center of curvature of the cornea of the eye to be inspected,
The arithmetic and control unit may be configured to obtain the corneal shape of the eye to be measured.

Further, the reference reflector of the present invention is formed as a model eye having at least a lens portion having a refractive power and a reflecting surface having a diffusing action, and at least the reflecting surface is formed to be finely movable. The control unit may be configured to finely move the model eye to remove noise, for example, a speckle pattern.

Further, the setting data obtained by the calculation control section of the present invention includes at least a rough spherical component of the eye to be measured, and the calculation control section sets the position of the reference reflecting surface or A configuration in which the refractive power of the lens unit is changed may be employed.

The setting data obtained by the arithmetic and control unit of the present invention may further include an astigmatism component of the eye to be measured, and the refractive power of the lens unit may be changed accordingly. .

Further, the reference reflector of the present invention is formed so as to be at least a reflecting surface having a predetermined curvature and to be movable in the optical axis direction, and the setting data obtained by the arithmetic and control unit includes at least the eye to be measured. The arithmetic control unit may include a shape corresponding to the shape of the cornea, and the arithmetic control unit may change the position of the reflection surface in the optical axis direction according to the setting data.

Further, the arithmetic and control unit according to the present invention is configured to move in the optical axis direction according to the setting data such that the convergence position of the light beam of the reference optical system and the center of curvature of the reflecting surface substantially coincide with each other. Can also.

The setting data obtained by the calculation control unit of the present invention further includes an astigmatism component of the eye to be measured, and the calculation control unit sets the refractive power of the lens unit in accordance with the setting data. May be changed.

A plurality of types of reference reflectors of the present invention are prepared, and can be configured to be selectable according to the optical characteristics of the eye to be examined.

Further, the switching section of the present invention can be constituted by a pair of analyzers respectively arranged in the measuring optical system and the reference optical system.

The switching section of the present invention includes a beam splitter, and this beam splitter may be constituted by a rhombic prism disposed in each of the measuring optical system and the reference optical system.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made in view of the above-mentioned problems. A first light source emits a light beam of a first wavelength, and a measuring optical system uses a light beam from the first light source for an object surface of an eye to be examined. Illuminates toward the surface of the subject, receives the light flux reflected back from the target surface of the eye to be inspected, and the reference optical system illuminates a minute area on the reflection surface of the reference reflector with the light flux from the first light source. A first conversion member converts the reflected light beam received by the measurement optical system or the reference optical system into a plurality of beams, and receives the light beam reflected from the reflection object and returns. The switching unit alternately guides the light beams of the measuring optical system and the reference optical system to the first light receiving unit, and the arithmetic control unit operates the measuring optical system obtained by the first light receiving unit. Optical characteristics of the subject's eye based on the light receiving position of the light beam from the camera and the light receiving position of the light beam from the reference optical system Door can be.

The arithmetic control unit of the present invention obtains setting data from an output signal of the first light receiving unit when receiving a light beam from the measuring optical system, and obtains a reference optical signal based on the obtained setting data. It is also possible to set the conditions of the reference reflector of the system.

Further, the object surface of the eye to be examined according to the present invention is a retina of the eye to be examined, the measuring optical system illuminates the retina of the eye to be examined with a light beam from the first light source in a minute area, and the arithmetic and control unit controls the operation of the eye to be measured. The optical properties of the refractive power can also be determined.

In the present invention, the target surface of the eye to be examined is the cornea to be examined, and the measuring optical system illuminates with a light beam from the first light source substantially toward the center of curvature of the cornea of the eye to be examined. The corneal shape of the eye can also be determined.

Further, the reference reflector of the present invention is formed as a model eye having at least a lens portion having a refractive power and a reflecting surface having a diffusing action, and at least the reflecting surface is formed to be finely movable. The unit can finely move the model eye to remove noise, for example, a speckle pattern.

Further, the setting data determined by the arithmetic control unit of the present invention includes at least a rough spherical component of the eye to be measured, and the arithmetic control unit determines the position of the reference reflecting surface or the lens unit in accordance with the setting data. The refractive power can also be changed.

The setting data obtained by the arithmetic and control unit of the present invention further includes an astigmatism component of the eye to be measured, and the refractive power of the lens unit can be changed accordingly.

The reference reflector of the present invention is formed so as to have a reflecting surface having at least a predetermined curvature and to be movable in the optical axis direction. The setting data obtained by the arithmetic and control unit includes at least the cornea of the eye to be measured. The arithmetic control unit may include a shape corresponding to the shape, and may change the position of the reflection surface in the optical axis direction according to the setting data.

Further, the arithmetic and control unit according to the present invention can be moved in the optical axis direction according to the setting data so that the convergence position of the light beam of the reference optical system and the center of curvature of the reflection surface substantially coincide.

The setting data obtained by the arithmetic control unit of the present invention further includes an astigmatism component of the eye to be measured, and the arithmetic control unit changes the refractive power of the lens unit according to the setting data. Can also.

Further, a plurality of types of reference reflecting portions of the present invention are prepared, and can be configured to be selectable according to the optical characteristics of the eye to be inspected.

Further, the switching section of the present invention may be a pair of analyzers respectively arranged in the measuring optical system and the reference optical system.

The switching section of the present invention includes a beam splitter, and this beam splitter can be constituted by a rhombic prism disposed in each of the measuring optical system and the reference optical system.

[0031]

【Example】

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]

As shown in FIG. 1, an eye characteristic measuring apparatus 10000 according to a first embodiment of the present invention includes a first light source unit 100 for emitting a light beam of a first wavelength, and a first light source unit 100. A first illumination optical system 200A for illuminating a minute area on the retina of the subject's eye with a light beam so that the illumination conditions thereof can be changed.
And a part of the luminous flux reflected from the retina of the subject's eye and returned
The first light receiving optical system 300A for guiding the reflected light beam to the first light receiving unit 510 via the first conversion member 400 for converting the reflected light beam into at least 17 beams, and the light beam from the second light source unit 110 are collected. Optical lens 360, beam splitter 3
A second illumination optical system 200B that illuminates the subject's eye 1000, which is an object, with substantially parallel light beams via the light beams 50 and 340, and a second light receiving unit 520 that reflects the second light beams returning from the anterior eye part and returning.
Based on the second light receiving optical system 300B for guiding the light to the first light receiving unit 510 corresponding to the inclination angle of the light beam.
And an arithmetic unit 600 for determining the optical characteristics of the eye to be inspected. Note that the first light source unit 100 corresponds to a first light source, and the first illumination optical system 200A corresponds to a measurement optical system.

The arithmetic section 600 controls the entire control including the control section 610. Further, the control unit 610 includes a first light receiving unit 510, a second light receiving unit 520, and a third light receiving unit 530.
And the signal from (11), and controls the blinking of the first to fourth light source units 100 to 130 and the driving of the first to fourth driving units 910 to 940 and displays the signals. The unit 700 controls the memory 800. Note that the signal from the first light receiving unit 510 can form setting data.

It is desirable that the first light source unit 100 has high spatial coherence and not high temporal coherence.
The first light source unit 100 of the first embodiment employs an SLD, and can obtain a point light source with high luminance.

Further, the first light source unit 100 of the first embodiment
Is not limited to the SLD, and even if the coherence is high in space and time like a laser, it can be used by appropriately reducing the time coherence by inserting a rotating diffusion plate or the like.

[0038] Even if the coherence is not high in space and time, such as SLD, if the light amount is sufficient, it can be used by inserting a pinhole or the like at the position of the light source in the optical path.

The first light source unit 10 for illumination of the first embodiment.
As the wavelength of 0, a wavelength in the infrared region, for example, 780 nm can be used.

The first illumination optical system 200A is for illuminating a minute area on the fundus of the eye with the light beam from the first light source unit 100. The first illumination optical system 200A includes the first illumination optical system 200A.
The light source unit 100, the first collimator lens 210, and the cylindrical lens 220 illuminate the eye 1000 to be inspected.

The first light receiving optical system 300 A is for receiving a light beam reflected and returned from the retina of the eye to be examined and guiding the light beam to the first light receiving unit 510. The first light receiving optical system 300A includes a first chopper 311A, a prism 331, a second afocal lens 312, and a first light receiving unit 301A. Further, the first light receiving unit 301A includes a first collimating lens 320, a conversion member 400 for converting the reflected light beam into at least 17 beams, and a first light receiving unit 510.

A beam splitter 331 is inserted into the first light receiving optical system 300A. The beam splitter 331 separates light from the first illumination optical system 200A, and passes one of the beams through the measuring optical system 201A. Eye 10
00, and the other is directed to the reference reflection unit 2000 via the reference optical path 202A.

Further, the beam splitter 331 transmits the scattered light scattered by the eye 1000 to be examined, reflects the scattered light scattered by the reference reflection surface 2000a, and guides the scattered light to the first light receiving optical system 300A. In FIG. 1, the beam splitter 331 is formed of a bonded prism having a beam splitter surface, but the beam splitter 331 may be formed of a pellicle which is a thin film. By forming the beam splitter 331 with a rhombic prism, the incident or exit surface is slightly inclined from the orthogonal with respect to the optical axis, and the effect of harmful reflected light can be reduced.

The reference optical path 202A is connected to the second chopper 31.
1B and a condenser lens 380. In the reference optical path 202A, a finely movable reference reflecting surface 230 is configured so that its position can be changed in accordance with the spherical component of the eye to be examined as setting data.

Here, the reference reflecting section 2000 is formed of at least a lens section having a refractive power and a reflecting surface having a diffusing action. The reference reflection unit 2000 corresponds to, for example, a model eye. The aberration of the lens unit used in the model eye is determined based on a value obtained from a design value and a value measured by an interferometer at a predetermined diopter position.
The fundus of the model eye is a diffusion plate.

Further, as shown in FIG. 10, the reference reflecting portion may be constituted by a glass rod 2000A having one surface formed by a spherical surface 240 and the other surface formed by a diffusing surface 242. Here, one spherical surface corresponds to the cornea, and the diffusing surface 2
Reference numeral 42 corresponds to the retina. In the case of refractive power measurement, the spherical surface 240 and the diffusing surface 24 are determined according to the spherical component of the eye to be examined.
A plurality of glass rods 2000A having different intervals up to 2 are prepared, and an appropriate glass rod is selected and measured according to the spherical component of the eye to be examined. If necessary, a spherical surface having a different radius of curvature or a spherical surface having a different radius of curvature and a different distance between the spherical surface 240 and the diffusion surface 242 may be prepared and selected.

In the case of corneal measurement, a plurality of glass rods 2000A having different radii of curvature of the spherical surface 240 according to the spherical component of the eye to be inspected are prepared, and the glass rods 2000A are appropriately selected according to the spherical component of the eye to be inspected. Select a rod and measure.

The distance L between the reference reflection unit 2000 and the fundus is adjusted in accordance with S of the eye 1000 to be examined. That is, L = f /
(1 + fD). Here, the focal length of the lens unit is f
, And the refractive power of the eye 1000 is D. The reference optical path 202A corresponds to a reference optical system.

If the first illumination optical system 200A is moved in the optical axis direction so that the point light source illuminates the retina of the eye 1000, the degree of convergence of the light beam can be changed.
In response to this change, the condenser lens 38 of the reference optical path 202A
0 so that the light flux of the first illumination optical system 200A converges on the reference reflection unit 2000 at least.
00, the condenser lens 380 is moved in the optical axis direction as necessary. This corresponds to adjustment of the so-called ocular axial length.

The first light receiving section 510 receives the light from the first light receiving optical system 300A that has passed through the conversion member 400, and
It is for generating a signal.

The eye 100 to be inspected corresponds to the first light source unit 100.
0 fundus and the reference reflecting surface 230 are conjugated,
The fundus of the subject's eye 1000 and the fundus of the reference reflection surface 230 (corresponding to the fundus of the model eye) and the first light receiving unit 510 are conjugate. Further, the conversion member 400 and the pupil are also conjugate, and the pupil and the pupil of the reference reflection surface 230 are conjugate.

That is, the front focal point of the first afocal lens 310 is substantially coincident with the anterior segment of the eye to be inspected, which is the object to be inspected.

The first illumination optical system 200A and the first light receiving optical system 300A assume that the light beam from the first light source unit 100 is reflected at a converging point, and the first light receiving unit 510 by the reflected light. The first light receiving unit 510 is configured to move in conjunction with each other while maintaining the relationship where the signal peak at the maximum becomes maximum, move in the direction in which the signal peak at the first light receiving unit 510 becomes strong, and stop at the position where the intensity becomes the maximum. ing. As a result, the first light source unit 1
The light flux from 00 will be converged on the fundus of the eye to be examined. It is desirable that the first light source unit 100 be configured to light up for a fixed short time after the preparation for measurement is completed.

Next, the conversion member 400 will be described.

The conversion member 400 arranged in the first light receiving optical system 300A is a wavefront conversion member for converting a reflected light beam into a plurality of beams. The conversion member 400 of the first embodiment includes:
A plurality of micro Fresnel lenses arranged in a plane orthogonal to the optical axis are employed.

In order to measure the measurement target portion up to the spherical component and other higher-order aberrations other than the third-order astigmatism, it is necessary to measure with at least 17 beams through the measurement target. An example of the conversion member is shown in FIGS. 9A and 9B. In each case, the center opening is arranged so as to coincide with the optical axis of the optical system.

Here, the micro Fresnel lens will be described in detail.

The micro Fresnel lens is an optical element having an annular zone at a height pitch for each wavelength and having a blaze optimized for emission parallel to the converging point. The micro Fresnel lens that can be used here has, for example, an optical path length difference of eight levels to which semiconductor fine processing technology is applied, and can achieve a light collection efficiency of 98%.

The light reflected from the fundus passes through the second afocal lens 312 and the collimating lens 320, passes through the conversion member 400, and becomes the first light receiving portion 5 as the primary light.
Focus on 10. Here, the zero-order light corresponds to the transmitted light flux,
The primary light corresponds to a convergent light beam.

The conversion member 400 may be constituted by a microlens portion that performs a convergence action or an opening portion that performs a diffraction action in each of at least 17 areas.

The conversion member 400 according to the first embodiment comprises a wavefront conversion member for converting a reflected light beam into at least 17 beams.

Next, the first light receiving section 510 is
Are used to receive a plurality of beams converted in the first embodiment. In the first embodiment, C
CD is adopted. Any type of CCD, such as a general low-noise type CCD or a 2000 * 2000-element cooled CCD for measurement, can be used.

The image signal output from the low-noise CCD and its driver can be easily realized by using an appropriate image input board.

Further, a working distance adjusting optical system for adjusting a working distance between the subject's eye 1000 to be examined and the optical characteristic measuring device 10000, and an optical axis orthogonal to the subject's subject's eye 1000 and the optical characteristic measuring device 10000. An alignment optical system for adjusting the positional relationship in the direction and a second illumination optical system 200B for illuminating the object are provided.

The alignment is performed as follows. Second
The light beam from the second light source unit 110 of the illumination optical system 200B is condensed by the condenser lens 360, the beam splitters 350,
The subject's eye 1000 to be inspected is illuminated with substantially parallel light beams through 40. The light beam reflected by the cornea of the subject's eye is emitted as a divergent light beam as if it were emitted from a point having a radius of 角 of the corneal curvature. This divergent light beam is transmitted to the second light receiving optical system 3.
The light is received as a spot image by the second light receiving unit 520 via the beam splitters 350 and 340 and the condenser lens 370 of 00B. If the spot image is off the optical axis on the second light receiving section 520, the main body of the optical characteristic measuring device 10000 is moved up and down and left and right so that the spot image is on the optical axis. When the spot image coincides with the optical axis on the second light receiving unit 520, the alignment adjustment is completed.

The wavelength of the second light source unit 110 is different from the wavelength of the first light source unit 100, and a longer wavelength, for example, 940 nm can be selected. Note that the second light source unit 110 and the pupil are conjugate, and the pupil and the second light receiving unit 520 are conjugate.

The beam splitter 340 is formed of a dichroic mirror that transmits the wavelength of the first light source unit 100 and reflects the wavelength of the second light source unit 110, so that the light beams of the other optical system are different from each other. Noise can be prevented.

Next, the working distance adjustment is performed by the fourth light source unit 13.
The light beam emitted from the vicinity of the optical axis emitted from the target lens 0 is irradiated toward the object, and the light reflected from the cornea of the eye to be inspected, which is the object, is received by the third light receiving unit 530 via the condenser lens 531 so that the light is emitted. Will be The third light receiving unit 530 only needs to be able to detect a change in the light flux position in a plane including the fourth light source unit 130, the optical axis, and the third light receiving unit 530. It can be constituted by an original CCD or a position sensing device (PSD).

When the subject's eye is at the proper working distance, a spot image from the fourth light source unit 130 is formed on the optical axis of the third light receiving unit 530. A spot image is formed above or below the optical axis.

Here, the electrical configuration of the optical characteristic measuring device 10000 will be described with reference to FIG. The electrical configuration of the eye characteristic measuring device 10000 includes an arithmetic unit 600, a control unit 610, a display unit 700, a memory 800, a first drive unit 910, a second drive unit 920, and a third drive unit. Drive unit 9
20 and a fourth drive unit 930.

The control unit 610 receives the first light source unit 100 to the fourth light source 13 based on a control signal from the arithmetic unit 600.
It controls the turning on and off of 0, and controls the first driving unit 910, the second driving unit 920, the third driving unit 930, and the fourth driving unit 940.

The first driving section 910 outputs the first signal based on the signal from the first light receiving section 510 input to the arithmetic section 600.
The first driving unit 910 for moving the entire illumination optical system 200A in the optical axis direction or for adjusting the rotation of the first cylinder lens 220 of the first illumination system 200A around the optical axis is an appropriate lens. The moving means is driven to move and adjust the illumination optical system 200A. Therefore, the first drive unit 910 moves the entire first illumination optical system 200A in the optical axis direction so that the point light source illuminates the retina of the subject's eye.

The second drive section 920 outputs the first signal based on the signal from the first light receiving section 510 input to the arithmetic section 600.
This is for moving the entire light receiving optical system 300A in the optical axis direction. The second drive unit 920 is configured to drive appropriate lens moving means to move and adjust the first light receiving optical system 301A.

The third driving section 930 is configured to control the first chopper 311A and the second chopper based on a control signal from the arithmetic section 600.
For controlling and driving the chopper 311B.

The first chopper 311A and the second chopper 311B placed on the exit side of the prism 331 correspond to a switching unit and correspond to an analyzer.
Light from the illumination optical system 200A can be alternately switched between the measurement optical system 201A and the reference optical path 202A.

When the arithmetic unit 600 drives the third driving unit 930 to open the first chopper 311A on the eye 1000 side and close the second chopper 311B on the model eye side, the measuring optical system 201A is activated. If the selected chopper 311A on the eye 1000 side is closed and the second chopper 311B on the model eye side is opened, the reference optical path 202A is opened.
Is selected.

The prism 331 is connected to the first illumination optical system 2
For separating the light into a measurement optical system 201A that reflects light from 00A to the subject's eye 1000 and a reference optical path 202A that transmits light from the first illumination optical system 200A to the reference reflection unit 2000. It is. The prism 331 may be a polarizing beam splitter. For example, a polarizing beam splitter that reflects S-polarized light and transmits P-polarized light may be used, and an analyzer that transmits S-polarized light or P-polarized light in the first light receiving optical system 300A. May be arranged.

The reference optical path 202A is connected to the second chopper 31
1B and a condenser lens 380. In the reference light path 202A, a finely movable reference reflection unit 2000 is arranged. Note that the reference reflection unit 2000 corresponds to a reference reflection object.

The fourth drive section 940 finely moves the reference reflection section 2000 based on a control signal from the arithmetic section 600. The reference reflection unit 2000 is formed of an appropriate diffusion plate. By slightly moving the reference reflection unit 2000, the influence of noise such as speckle can be removed. The reference reflecting unit 2000 may be of a revolver type and may be configured so that several types can be exchanged.

The fourth driving section 940 is provided, for example, in FIG.
As shown in (a), the reference reflection unit 2000 is disposed on a rail 2100 that can move to the left and right, the reference reflection unit 2000 stands up against the elastic restoring force of the spring 2200, and the piezo unit 2300 is driven. As a result, the reference reflection unit 200
0 can be moved.

As shown in FIG. 3B, the fourth driving section 940 can be configured such that the motor 2400 is connected to the reference reflection section 2000 and the reference reflection section 2000 is rotated.

Further, as shown in FIG. 3B, the fourth drive section 940 can attach the reference reflection section 2000 to a stage 2500 that can move in a two-dimensional direction, and can finely move the reference reflection section 2000.

First, the overall measurement will be described with reference to FIG.

First, measurement is started in S1. Next, in S2, the calculation unit 600 drives the third driving unit 930 to open the first chopper 311A on the eye 1000 side and the second chopper 311 on the model eye side for measurement of setting data.
Close 11B.

In S3, FIG.
Is performed, the measurement result of the eye to be inspected including the aberration present in the first light receiving optical system is measured, and the reference reflection unit 2000 is set in accordance with the eye to be inspected. Setting data is required. Specifically, the setting data is obtained from a shift amount of the center of gravity obtained from the spot image obtained from the subject's eye from the center of gravity obtained from the temporarily given spot image of emmetropia (S, C, A _X )
It is.

In S4, the arithmetic section 600 drives the third drive section 930 based on the setting data obtained in S3, opens the second chopper 311B on the model eye side, and opens the first chopper 311B on the eye 1000 side. Close the chopper 311A.

In S5, "measurement of reference reflection section (A-1)" in FIG. 4 is executed. In other words, the reference reflecting section is formed by the condenser lens section 380 and the reference reflecting surface 2 in accordance with the refractive power of the eye to be examined.
Thirty intervals are adjusted. Specifically, the interval L = f / (1 + fD) is set according to the refractive power and the corneal curvature of the eye to be examined. Here, the focal length of the lens unit is f, and the refractive power of the eye 1000 is D.

Further, in S6, the shift amount of the center of gravity of the spot image on the first light receiving unit 510 between the eye 1000 to be inspected and the reference reflecting unit 2000 (model eye) is calculated.

In S7, a Zernike coefficient is calculated based on the fourth and fifth equations described later.

In S8, the calculated values (S, C, A
_X , SA, Coma,...) Are displayed on the display unit 700.

Then, in S9, it is determined whether or not to end the measurement.
If the measurement is not completed in S10, the process returns to S2.

The processing of "measurement of eyes (A-2)" performed in S3 in the above-described flowchart will be described below with reference to FIG.

"Measurement of eyes (A-2)"

In step 1 (hereinafter abbreviated as S1), measurement is started. Next, in S2, the alignment of the position of the subject's eye is adjusted.

At S3, the first light receiving section 510 picks up a spot image. Next, the center of gravity is detected in S4.

Further, in S5, the amount of deviation from the center of gravity of the emmetropia is calculated. Here, the center-of-gravity position of the emmetropia refers to the center of gravity of the condensed light beam formed on the first light receiving portion 510 by the conversion member 400 when the light beam reflected from the fundus of the eye is measured when measuring the eye to be examined. are doing.

Then, in S6, a fourth formula and a fifth formula described later are used.
The Zernike coefficient is calculated based on the equation. After calculating the Zernike coefficient in S6, the process proceeds to S7 to end the measurement.

The processing of “measurement of reference reflection section (A-1)” performed in S5 in the above-described flowchart will be described below with reference to FIG.

"Measurement of Reference Reflector (A-1)"

The measurement of the reference reflector will be described with reference to FIG. In step 1 (hereinafter abbreviated as S1), measurement is started. Next, in S2, (S, C,
A reference reflection unit 2000 (model eye) close to A _X ) is installed. Then, in S3, image data is acquired from the first light receiving unit 510.

In step S4, the position of the center of gravity is detected. The position of the center of gravity can be determined, for example, such that the projected light beam is projected on a plurality of pixels on the light receiving surface, and the intensity of the light beam of each pixel is referred to. By calculating the center of gravity in this way, it is possible to ensure a measurement position accuracy of 1/10 or less of the element. After detecting the position of the center of gravity in S4, the measurement of the reference reflection unit 2000 ends in S5.

[Second Embodiment]

An optical characteristic measuring apparatus 2 according to a second embodiment of the present invention.
0000 is an optical configuration for measuring a corneal shape. As shown in FIG. 7, the optical configuration is substantially the same as in the first embodiment, and the cornea is configured to be measurable.

With reference to FIG. 7, a description will be given mainly of points different from the first embodiment. In the light receiving optical system, the output of the third light receiving unit 530, which is a working distance optical system, appropriately adjusts the working distance and the second light receiving unit 520 of the alignment optical system.
The first light receiving unit 510 is arranged so as to have a conjugate relationship with the center of curvature of the cornea of the eye to be examined via the objective lens 310 and the collimating lens 320 in a state where appropriate alignment adjustment is performed by the output of. That is, the first light source 100
And the center of curvature of the cornea of the subject's eye 1000 are conjugate, and the center of curvature of the reference reflecting unit 2000 (model eye) and the first light receiving unit 5
And 10 are conjugate. Furthermore, the second light source 110 and the pupil of the eye 1000 are conjugate, and the pupil and the second light receiving unit 520 are conjugate.

The alignment is performed as follows. Second
The light beam from the second light source unit 110 of the illumination optical system 200B is condensed by the condenser lens 370, the beam splitters 350 and 340.
Illuminates the subject's eye 1000 as an object with substantially parallel light beams. The light beam reflected by the cornea of the subject's eye is emitted as a divergent light beam as if it were emitted from a point having a radius of 角 of the corneal curvature. This divergent light beam is transmitted to the second light receiving optical system 300.
The light is received as a spot image by the second light receiving unit 520 via the beam splitters 350 and 340 and the condenser lens 370 of B. If the spot image is off the optical axis on the second light receiving section 520, the main body of the optical characteristic measuring device 10000 is moved up and down and left and right so that the spot image is on the optical axis. When the spot image coincides with the optical axis on the second light receiving unit 520, the alignment adjustment is completed.

The wavelength of the second light source unit 110 is different from the wavelength of the first light source unit 100, and a longer wavelength, for example, 940 nm can be selected.

The anterior focal position of the second afocal lens 312 is substantially the same as the cornea of the eye to be examined, unlike the first embodiment.

Similarly, with the proper working distance and the proper alignment adjustment, the first illumination optical system 200
The first illumination optical system 200A is moved and adjusted so that the illumination light beam of A converges toward the center of curvature of the cornea of the eye 1000 to be inspected. Whether the illumination light beam of the first illumination optical system 200A is correctly converged toward the center of curvature of the cornea of the eye 1000 to be examined is determined by finely moving the first illumination optical system 200A in the direction of the optical axis. The movement and adjustment are performed so that the output of the light receiving unit 510 is maximized.

First, the corneal shape is adjusted such that the light from the first illumination optical system 200A converges to the center of the corneal curvature with the appropriate working distance adjusted.
And the first light receiving optical system 300A is moved in conjunction therewith, and the corneal vertex position and the convergence of the first light receiving optical system 300A when the output of the first light receiving unit 510 of the first light receiving optical system 300A is maximized. The distance to the position will correspond to the radius of curvature of the cornea.

That is, the working distance adjustment is completed.

If the first illumination optical system 200A is moved in the direction of the optical axis so that the light beam converges to the center of curvature of the cornea of the eye 1000, the degree of convergence of the light beam can be changed. Accordingly, the lens 3 of the reference optical path 202A
80, the luminous flux of the first illumination optical system 200A is
Lens 3 so that it converges toward the center of curvature in front of 80
80 is moved in the optical axis direction. This corresponds to adjustment of the so-called ocular axial length.

Since the specific measuring method and procedure in the second embodiment are substantially the same as those in FIG. 6 described in the first embodiment, detailed description thereof will be omitted.

The obtained Zernike polynomials represent the optical characteristics (shape, radius of curvature, power, etc.) of the cornea.

The other configuration, operation, and the like are the same as those of the first embodiment, and thus description thereof is omitted.

[Third Embodiment]

The optical characteristic measuring apparatus 10000 for measuring refractive power according to the first embodiment and the optical characteristic measuring apparatus 20000 for measuring a corneal shape according to the second embodiment can be combined.

"Measurement principle"

Here, the principle of operation of the calculating section 600 for obtaining the optical characteristics of the eye 1000 based on the inclination angle of the light beam obtained by the first light receiving section 510 will be described in detail.

What is measured by the present invention is the wavefront aberration of the eye.

If the vertical and horizontal coordinates of the conversion member 400 are X and Y, and the vertical and horizontal coordinates of the first light receiving unit 510 are x and y,

In general, the wavefront W (X, Y) represented by the following equation (3)
Is related by the following first and second equations.

"Equation 1"

... Equation 1

"Equation 2"

..... the second expression

"Equation 3"

..... the third formula

Therefore, both sides of the third expression are converted to conversion members 400
By differentiating with the above coordinates X and Y and substituting the left side of the first and second equations, a polynomial of C _ij can be obtained.

Note that Z _{ij in} the third equation is called Zernike polynomial, and is represented by the following fourth and fifth equations.

[Equation 4]

..... Formula 4

"Equation 5"

.... Formula 5

The unknown _Cij can be obtained by minimizing the square error of the following equation (6).

"Equation 6"

.... Formula 6

By using C _ij obtained as described above, it can be used as an optically important parameter of the eye.

Here, the meaning of the Zernike polynomials will be described.

Z ₁₀ , Z ₁₁ Tilt Z ₂₁ Defocus Z ₂₀ , Z ₂₂ Third-order astigmatism Z ₃₀ , Z ₃₃ Sagittal aberration Z ₃₁ , Z ₃₂ Third-order coma Z ₄₂ Third-order spherical aberration Z ₄₁ , Z ₄₃ 5-order astigmatism Z _{52, Z 53} 5-order coma aberration Z ₆₃ 5-order spherical aberration Z ₈₄ 7-order spherical aberration

[Regarding Removal of Aberration of Device by Reference Reflecting Unit 2000]

The XY plane (pupil) and the X1-Y1 plane (Hartmann plate) are optically conjugate (magnification: β). f
Is the distance from the Hartmann plate (400) to the CCD (first light receiving unit 510), and is equal to the focal length of the micro lens of the Hartmann plate (400).

As shown in FIG. 8, X2 is the Hartmann image point position when the optical system of the measuring device has no aberration, X2 'is the Hartmann image point position of the measuring device with only aberration, and X2 ″ is the eye 1000 to be examined. Assuming that the Hartmann image point position includes the aberration of

[0143] wavefront aberration W _T containing the aberration of the measurement optical system of the aberration and the measuring apparatus of the eye 1000 is expressed by the following equation.

"Equation 7"

..... Formula 7

The following holds.

[0147] Hereinafter, in the expression relating to Y, since X may be replaced with Y, it is omitted.

[0148] Here, if the W _R and wavefront aberration of the measurement optical system of the measuring device,

[Equation 8]

.... Equation 8

[0151] In this case, if the _{W E} and the wavefront aberration of the measurement eye,

[Equation 9]

... Equation 9

[0154] X2 is also considered a reference point on the calculations, the calculations and the reference point of this point, contains both the aberration of the aberration and the measuring apparatus of the eye to the wavefront aberration W _T. Therefore,
In order to cancel the aberration of the device, in the related art, the aberration of the device is measured using a test object having no aberration in advance.

However, in this method, since the data measured at the beginning is used, the distortion of the equipment generated after that, and the aberration of the equipment due to the deformation due to the temperature and the like are included.
Therefore, W _T : the aberration of the reference reflection unit 2000 + the aberration generated after the initial measurement.

In the present invention, the reference optical path is measured each time, and the position of the spot measured there is set to X2 ', whereby aberrations at the time of measurement can be completely removed, and extremely accurate measurement can be performed. .

That is, using the eighth equation,

"Equation 10"

.... Formula 10

Can be obtained.

[0161]

According to the present invention constructed as described above, a first light source for emitting a light beam of a first wavelength, and a light beam from the first light source is illuminated toward a target surface of an eye to be examined, and the eye to be examined A measurement optical system for receiving a light beam reflected from the target surface and returned,
A reference optical system for illuminating a minute area on the reflection surface of the reference reflector with a light beam from the first light source and receiving a light beam reflected back from the reference reflector, and the measurement optical system or A first conversion member for converting the reflected light beam received by the reference optical system into a plurality of beams, a first light receiving unit for receiving the plurality of light beams converted by the conversion member, and the measurement optical system A switching unit for alternately guiding the light beam of the reference optical system to the first light receiving unit; a light receiving position of the light beam from the measurement optical system obtained by the first light receiving unit; and a light receiving position of the light beam from the reference optical system. Since it is composed of an arithmetic control unit for obtaining the optical characteristics of the subject's eye based on the position, aberrations at the time of measurement can be completely removed, and an outstanding effect that extremely accurate measurement can be performed. is there.

[0158]

[Brief description of the drawings]

FIG. 1 is an optical characteristic measuring apparatus 100 according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a 00.

FIG. 2 is a diagram showing an electrical configuration of an optical characteristic measuring device 10000 of the first embodiment.

FIG. 3A is a diagram illustrating an example of a fourth driving unit 940.

FIG. 3B is a diagram illustrating an example of a fourth driving unit 940.

FIG. 3C is a diagram illustrating an example of a fourth driving unit 940.

FIG. 4 is a diagram illustrating the operation of the first embodiment.

FIG. 5 is a diagram illustrating the operation of the first embodiment.

FIG. 6 is a diagram illustrating the operation of the first embodiment.

FIG. 7 is a diagram illustrating an optical configuration of an optical characteristic measuring device 20000 according to a second embodiment.

FIG. 8 is a diagram illustrating the principle.

FIG. 9 is a diagram illustrating an opening of a Hartmann plate.

FIG. 10 is a diagram illustrating a reference reflection unit.

[Explanation of symbols]

 10000 Optical property measuring device of first embodiment 20000 Optical property measuring device of second embodiment 1000 Eye to be inspected 2000 Reference reflecting unit 100 First light source unit 110 Second light source unit 120 Third light source unit 130 Fourth light source Section 200A First illumination optical system 220 Cylinder lens 300A First light receiving optical system 300B Second light receiving optical system 310 Objective lens 311A First chopper 311B Second chopper 320 Collimating lens 331 Prism 340 Beam splitter 350 Beam splitter 400 First conversion Member 510 First light receiving section 520 Second light receiving section 530 Third light receiving section 600 Calculation section 700 Display section

Claims (13)

[Claims] 1. A first light source for emitting a light beam of a first wavelength, and a light beam from the first light source is illuminated toward a target surface of an eye to be examined, and is reflected back from the target surface of the eye to be examined. A measuring optical system for receiving the light beam, and a light beam from the first light source for illuminating a minute area on the reflection surface of the reference reflector and receiving a light beam reflected from the reference reflector and returned. A reference optical system, a first conversion member for converting a reflected light beam received by the measurement optical system or the reference optical system into a plurality of beams, and a plurality of light beams converted by the conversion member. A first light receiving unit, and a switching unit for alternately guiding the light beams of the measurement optical system and the reference optical system to the first light receiving unit;
An arithmetic control unit for obtaining optical characteristics of the eye to be examined based on the light receiving position of the light beam from the measuring optical system and the light receiving position of the light beam from the reference optical system obtained by the first light receiving unit. Characteristic measuring device. 2. An arithmetic control unit obtains setting data from an output signal of the first light receiving unit when receiving a light beam from a measuring optical system, and based on the setting data obtained here, sets the reference optical system. 2. The eye characteristic measuring apparatus according to claim 1, wherein the apparatus is configured to set a condition of a reference reflector of the system. 3. The eye surface to be inspected is an eye retina to be inspected, and the measurement optical system is configured to illuminate the eye retina to be inspected in a minute area with a light beam from the first light source. 3. The eye characteristic measuring apparatus according to claim 2, wherein the optical characteristic of the refractive power of the eye to be measured is obtained. 4. The eye surface to be inspected is a cornea to be inspected, and the measurement optical system is configured to illuminate with a light beam from the first light source substantially toward a center of curvature of the cornea of the eye to be inspected, 3. The eye characteristic measuring device according to claim 2, wherein the control unit obtains a corneal shape of the eye to be measured. 5. The reference reflector includes a lens portion having at least a refractive power and a reflection surface having a diffusing action, and at least the reflection surface is a model eye formed to be finely movable. The eye characteristic measuring device according to claim 2 or 3, wherein the eye drive device finely drives the model eye to remove noise, for example, a speckle pattern or the like. 6. The setting data obtained by the arithmetic control unit includes at least a rough spherical component of the eye to be measured, and the arithmetic control unit sets the position of the reference reflecting surface or the lens in accordance with the setting data. The eye characteristic measuring apparatus according to claim 5, wherein the refractive power of the portion is changed. 7. The eye according to claim 6, wherein the setting data obtained by the arithmetic control unit further includes a rough astigmatism component of the eye to be measured, and the refractive power of the lens unit is changed accordingly. Characteristic measuring device. 8. The reference reflector is a reflection surface having at least a predetermined curvature, and is formed so as to be movable in an optical axis direction.
The setting data obtained by the arithmetic control unit is assumed to include at least data corresponding to the approximate shape of the cornea of the eye to be measured, and the arithmetic control unit shifts the reflecting surface in the optical axis direction according to the setting data. 5. The eye characteristic measuring device according to claim 2, wherein the position of the eye characteristic is changed. 9. The arithmetic control unit according to the setting data,
9. The eye characteristic measuring device according to claim 8, wherein the eye characteristic measuring device is moved in the optical axis direction such that a convergence position of a light beam of the reference optical system substantially coincides with a center of curvature of the reflection surface. 10. The setting data obtained by the arithmetic control unit further includes an astigmatism component of a rough cornea shape of the eye to be measured, and the arithmetic control unit sets the lens in accordance with the setting data. The eye characteristic measuring device according to claim 9, wherein the refractive power of the part is changed. 11. The eye characteristic measurement according to claim 1, wherein a plurality of types of reference reflection units are prepared and selectable according to the optical characteristics of the eye to be inspected. apparatus. 12. The eye characteristic measuring apparatus according to claim 1, wherein the switching unit includes a pair of analyzers arranged in the measuring optical system and the reference optical system, respectively. 13. The switching unit according to claim 1, wherein the switching unit includes a beam splitter, and the beam splitter includes a rhombic prism disposed in each of the measuring optical system and the reference optical system. Item 2. An eye characteristic measuring device according to item 1.